ci: add detailed failing audits and HTML reports to Lighthouse CI

- Output both JSON and HTML from Lighthouse runs
- Extract failing audits per category into the PR comment using
  collapsible details blocks
- Upload HTML reports as build artifacts (14-day retention)
- Link to artifacts from the comment template

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rlespinasse

.github/comment-templates/lighthouse-report.md

@@ -7,3 +7,5 @@
 {{results}}
 
 All categories must score 90 or higher.
+
+Full HTML reports are available as [build artifacts](../actions).

.github/workflows/lighthouse.yaml

@@ -28,6 +28,14 @@ jobs:
         id: lighthouse
         run: just lighthouse
 
+      - name: Upload Lighthouse HTML reports
+        if: always()
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+        with:
+          name: lighthouse-reports
+          path: /tmp/lighthouse-*.report.html
+          retention-days: 14
+
       - name: Load results for PR comment
         if: always() && github.event_name == 'pull_request'
         run: |

justfile

@@ -209,23 +209,42 @@ lighthouse: build
         url="http://localhost:{{ port }}${page}"
         echo "Testing $url..."
 
+        base_path="/tmp/lighthouse-${page//\//-}"
         npx lighthouse "$url" \
             --chrome-flags="--headless=new --no-sandbox" \
-            --output=json \
-            --output-path=/tmp/lighthouse-${page//\//-}.json \
+            --output=json,html \
+            --output-path="$base_path" \
             --disable-full-page-screenshot \
             --throttling-method=devtools \
             > /dev/null 2>&1 || true
 
-        if [ -f "/tmp/lighthouse-${page//\//-}.json" ]; then
-            perf=$(jq '.categories.performance.score * 100' "/tmp/lighthouse-${page//\//-}.json")
-            access=$(jq '.categories.accessibility.score * 100' "/tmp/lighthouse-${page//\//-}.json")
-            bp=$(jq '.categories."best-practices".score * 100' "/tmp/lighthouse-${page//\//-}.json")
-            seo=$(jq '.categories.seo.score * 100' "/tmp/lighthouse-${page//\//-}.json")
+        json_file="${base_path}.report.json"
+        if [ -f "$json_file" ]; then
+            perf=$(jq '.categories.performance.score * 100' "$json_file")
+            access=$(jq '.categories.accessibility.score * 100' "$json_file")
+            bp=$(jq '.categories."best-practices".score * 100' "$json_file")
+            seo=$(jq '.categories.seo.score * 100' "$json_file")
 
             printf "Page: %-20s | Perf: %3.0f | A11y: %3.0f | BP: %3.0f | SEO: %3.0f\n" "$page" "$perf" "$access" "$bp" "$seo"
             results_md+=$'\n'"- **$page**: Performance $perf, Accessibility $access, Best Practices $bp, SEO $seo"
 
+            # Extract failing audits for categories below 90
+            failing_audits=$(jq -r '
+                .audits as $audits |
+                .categories | to_entries[] | select(.value.score < 0.9) |
+                .key as $cat |
+                [.value.auditRefs[].id |
+                 $audits[.] |
+                 select(.score != null and .score < 0.9) |
+                 "    - " + .title + " (" + (.score * 100 | floor | tostring) + ")"] |
+                select(length > 0) |
+                "  - **" + $cat + "**:\n" + join("\n")
+            ' "$json_file" 2>/dev/null || true)
+
+            if [ -n "$failing_audits" ]; then
+                results_md+=$'\n'"  <details><summary>Failing audits</summary>"$'\n'$'\n'"$failing_audits"$'\n'"  </details>"
+            fi
+
             for score in "$perf" "$access" "$bp"; do
                 if (( $(echo "$score < 90" | bc -l) )); then
                     all_passed=false